A new protocol called SPUD (for “Substrate Protocol for User Datagrams”), which provides for the broadcasting of recommendation messages in a communications network between endpoints and entities in the network supporting this communication, is currently being finalized by the IETF (for “Internet Engineering Task Force”) standardization authority. The IETF document “draft-hildebrand-spud-prototype-03” dated Mar. 9, 2015 and entitled “Substrate Protocol for User Datagrams (SPUD) Prototype” sets out, notably, a prototype SPUD protocol. According to this document, the SPUD protocol allows communication between two terminal points (known as “endpoints” in English) of a network via a “tube”. In the terminology of this document, a tube is defined more particularly as a grouping of packets between two endpoints of the network. Such a tube is created by the endpoint that initiates a call to the second endpoint, and may be closed by one or other of the endpoints. The prototype SPUD protocol provides for two types of recommendation messages in the form of data packets called “packets carrying recommendation data relating to the application” (“Application Data packets”) and data packets called “packets carrying recommendation data relating to the network path” (“Advisory Path Data packets”). The packets carrying application data are sent by endpoints. Each entity in the network participating in the tube created for the call relays these data packets to the recipient entity of the packets. For their part, the packets carrying recommendation data relating to the network path are sent by a control entity located on a network path of the tube between the two endpoints.
The prototype SPUD protocol proposed in the IETF document has a number of drawbacks. Specifically, according to this protocol, non-certified information from a sub-network participating in the establishment of the tube is transmitted to the endpoints, and the same non-certified information is taken into account in the recommendation messages. In fact, inappropriate recommendation messages may be sent and exchanged. By sending inappropriate recommendations, such messages may also cause a degradation of the network conditions, such as network congestion or a failure of network equipment.